JP2007018534A - Online system recovery method, implementation device thereof, and recording medium in which processing program thereof is recorded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of switching an active online system to a standby online system in the case of trouble at high speed. <P>SOLUTION: The online system recovery method by which business processing is switched from an active online system to a standby online system and is continued when the active online system fails comprises a step for transferring log information showing a reference history showing a history of the reference processing conducted by the active online system and an update history showing a history of update processing, a step for implementing tracking processing which conforms the contents of an input/output buffer in the standby online system to the contents of an input/output buffer in the active online system according to the transferred log information, and a step for monitoring the operational status of the active online system executing business processing, and, when trouble is detected in the running online system, the standby online system continues the business processing using the input/output buffer subjected to tracking processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an online processing system that requires high-speed recovery processing accompanying a system stop, and more particularly to a technique that is effective when applied to an online processing system such as an online database system in which a large number of update transactions occur.

  In a conventional general online system recovery method, log information, which is history information necessary for system recovery, is stored on an external storage device by the execution online system for recovery processing when the execution online system stops due to a failure. When a failure occurs in the execution online system, which is stored in the log file, the standby online system reads the log information and executes processing necessary for system recovery.

  As this speed-up technique, for example, one disclosed in Japanese Patent Application Laid-Open No. Sho 62-57030 is known. The outline of this technique is that log information on an external storage device shared between host computers is recorded before a failure occurs. The standby online system reads the log information, and the standby online system tracks the processing before the execution online system stops, thereby reducing the amount of log information read when a failure occurs.

  In addition, as described in Japanese Patent Laid-Open No. 2-77743, log information is stored in a log file on an external storage device shared between host computers in an execution online system, and is also stored in an extended storage device shared between host computers. Is also stored at the same time, and in the system recovery process in the standby online system after a failure occurs in the execution online system, the log information is read from this extended storage device, thereby eliminating the reading of the log information from the external storage device It has been known.

  Further, as described in Japanese Patent Laid-Open No. 10-49418, log information of the execution online system is transferred to the standby online system by communication, and the tracking process is performed in the standby online system before switching due to a failure occurs. Thus, there is known a method for speeding up recovery after a failure occurs.

  However, the technique described in Japanese Patent Application Laid-Open No. 62-57030 needs to input log information after a checkpoint from a log file on an external storage device after switching to a standby online system due to a failure. Depending on the interval between checkpoints, a large amount of log information is read, which is a major factor that hinders high-speed system recovery. On the other hand, if the interval between checkpoints is reduced in order to reduce the amount of log information to be read after switching due to a failure, there is a problem of increasing the overhead in the execution online system.

  Although the technique described in Japanese Patent Laid-Open No. 2-77743 speeds up the reading of log information, as with the technique described in Japanese Patent Laid-Open No. 62-57030, switching to a standby online system due to a failure is performed. After this occurs, it is necessary to read log information after the checkpoint, and depending on the interval between checkpoints, a large amount of log information is read, which is a major factor that hinders the realization of high-speed system recovery. On the other hand, if the interval between checkpoints is reduced in order to reduce the amount of log information to be read after switching due to a failure, there is a problem of increasing the overhead in the execution online system.

  In addition, the technology described in Japanese Patent Laid-Open No. 10-49418 transfers log information of an execution online system to the standby online system by communication, and performs tracking processing in the standby online system before switching due to a failure occurs. However, since the tracking process is performed using only the log information of the update history, the result of the reference process such as the reference to the index performed in the execution online system is not reflected in the memory of the standby online system. However, there is a problem that the efficiency of reference processing such as index search is reduced when switching due to a failure occurs. In addition, since external storage devices such as log files and databases are not shared, there is a problem that twice as many external storage devices are required. There is a problem in that continuous operation cannot be realized for 24 hours 365 days because it is necessary to suspend the execution of the transaction for the purpose of consistency when returning to the system.

  An object of the present invention is to provide a technique capable of solving the above-described problem and switching to a standby online system at a high speed when a failure occurs in an execution online system.

  Another object of the present invention is to provide a technique capable of reducing the transfer load of log information for matching the contents of the input / output buffer in the standby online system with the contents of the input / output buffer in the execution online system. It is in.

  Another object of the present invention is a technology capable of re-establishing a hot standby state without affecting the execution of business processing in the execution online system when the standby online system is restarted after failure or maintenance. Is to provide.

  The present invention relates to the contents of the input / output buffer of the execution online system when a failure occurs in the execution online system in the online processing system that switches the business process to the standby online system and continues when the failure occurs in the execution online system. Business processing is continued in the standby online system using the input / output buffer of the standby online system that has been matched in advance.

  In the present invention, log information representing the reference history indicating the history of the reference processing performed in the execution online system and the update history indicating the history of the update processing during the execution of the execution online system is transferred to the standby online system, and the log In the standby online system that has received the information, in accordance with the transferred log information, processing corresponding to the reference processing and update processing performed in the input / output buffer of the execution online system is performed on the input / output buffer of the standby online system, A tracking process is executed to match the contents of the input / output buffer in the standby online system with the contents of the input / output buffer in the execution online system.

  In addition, the operational status of the execution online system that is executing the business process is monitored, and when a failure of the execution online system is detected, the business process is waited for using the input / output buffer that has been subjected to the tracking process. To continue.

  As described above, according to the present invention, an online system with less overhead in the execution online system while eliminating the input of log information from the log file on the external storage device after the switch to the standby online system due to a failure occurs. Recovery method can be realized.

  As described above, according to the online processing system of the present invention, when a failure occurs in the execution online system, the input / output buffer of the standby online system that has been matched in advance with the contents of the input / output buffer of the execution online system is used. Since the business processing is continued in the standby online system, it is possible to switch to the standby online system at high speed when a failure occurs in the execution online system.

  According to the present invention, when a failure occurs in the execution online system, business processing is continued in the standby online system using the input / output buffer of the standby online system that has been matched in advance with the contents of the input / output buffer of the execution online system. Therefore, when a failure occurs in the execution online system, it is possible to switch to the standby online system at high speed.

  The following describes an online processing system according to an embodiment that switches business processing to a standby online system and continues when a failure occurs in the execution online system.

  FIG. 1 is a diagram showing a schematic configuration of an online processing system according to the present embodiment. As shown in FIG. 1, the host computer 10 of this embodiment has a monitor processing unit 11, a log output processing unit 15, and a log transfer processing unit 16.

  The monitor processing unit 11 is a processing unit that monitors the operating state of the partner system by exchanging control messages for mutual monitoring with the monitor processing unit 21. The log output processing unit 15 is a processing unit that outputs log information stored in the log I / O buffer 14 to a storage device shared by the execution online system 12 and the standby online system 22.

  The log transfer processing unit 16 is a processing unit that transfers log information indicating a reference history indicating a history of reference processing performed in the execution online system 12 and an update history indicating a history of update processing to the standby online system 22.

  A program for causing the host computer 10 to function as the monitor processing unit 11, the log output processing unit 15 and the log transfer processing unit 16 is recorded on a recording medium such as a CD-ROM and stored in a magnetic disk or the like and then loaded into a memory. To be executed. The recording medium for recording the program may be a recording medium other than the CD-ROM.

  The host computer 20 has a monitor processing unit 21 and a tracking processing unit 27. The monitor processing unit 21 exchanges control messages for mutual monitoring with the monitor processing unit 11 to monitor the operating state of the execution online system 12 that is executing the business process. When a failure is detected, it is a processing unit that causes the standby online system 22 to continue the business process using the database I / O buffer 23 on which the tracking process has been performed.

  The tracking processing unit 27 performs tracking processing for matching the contents of the database I / O buffer 23 in the standby online system 22 with the contents of the database I / O buffer 13 in the execution online system 12 according to the transferred log information. Is a processing unit.

  A program for causing the host computer 20 to function as the monitor processing unit 21 and the tracking processing unit 27 is recorded on a recording medium such as a CD-ROM and stored in a magnetic disk, and then loaded into a memory and executed. To do. The recording medium for recording the program may be a recording medium other than the CD-ROM.

  The online processing system according to the present embodiment includes an execution online host computer 10, an execution online monitor processing unit 11, an execution online execution online system 12 (for example, a database management system), and a standby online host computer. 20, a monitor processing unit 21 on the standby online side, and a standby online system 22 (for example, a database management system) on the standby online side.

  A log file 30 and a database 40 for storing log information 31 are stored on a nonvolatile storage device (generally a magnetic disk device) shared by the execution online system 12 on the execution online side and the standby online system 22 on the standby online side. Have.

  Furthermore, the online processing system according to the present embodiment includes the database I / O buffer 13 used by the execution online system 12 for inputting / outputting records with the database 40, and the log information 30 inputting / outputting log information with the execution online system 12. Log I / O buffer 14 used for storage, database I / O buffer 23 used by standby online system 22 to input / output records to / from database 40, and log information input / output from standby online system 22 to log file 30 And a log I / O buffer 24 used for the above.

  The execution online system 12 outputs log information stored in the log I / O buffer 14 to the log file 30, and the execution online system 12 is stored in the log I / O buffer 14. A log transfer processing unit 16 that transfers log information to the log information reception buffer 25 of the standby online system 22 and a tracking process in the standby system in parallel with the business process in the execution online system 12 according to the transferred log information To the standby online system 22 from the execution online system 12 and the communication medium 50 for exchanging control messages (Alive messages) for mutual monitoring between the monitor processor 11 and the monitor processor 21. Log file 3 using the communication medium 51 for transferring the log information and the standby online system 22 And a log I / O buffer 24 for inputting a log information 31 above.

  Here, the communication medium 50 and the communication medium 51 may be physically one. However, in order to prevent malfunction due to the transmission delay of the control signal when the log information transfer traffic becomes high, separate communication is performed in this embodiment. As a medium.

  Further, the database I / O buffer 13, the log I / O buffer 14, the database I / O buffer 23, the log I / O buffer 24, and the log information reception buffer 25 may be one each, but performance / reliability In order to ensure the performance, buffering is performed with a plurality of buffers each.

  1 shows the log output processing unit 15 and the log transfer processing unit 16 in the execution online system 12 and the tracking processing unit 27 in the standby online system 22, but the execution online system 12 and the standby online system 22 Suppose that there is no difference in the functions that are implemented, and the behavior only changes depending on whether it is an execution system or a standby system.

  Therefore, when a failure occurs in the host computer 10 and the right to execute the transaction is switched to the host computer 20 and the standby online system 22 starts the transaction service, the standby online system 22 becomes the execution system, and after the failure recovery of the host computer 10 The execution online system 12 becomes a standby system.

  FIG. 2 is a flowchart showing a processing procedure of the execution online system 12 and the standby online system 22 of the present embodiment. As shown in FIG. 2, when the execution online system 12 of this embodiment is activated, it first performs an initial setting process (step 122).

  In this initial setting process, loading of processing programs, importing various definition information and execution parameters, creating a control table in virtual memory, opening a database, starting a transaction execution space (also called an execution process), etc. The log information at the end of the log file is detected and stored. Here, buffer reservation, page fixing, buffer position information exchange, and the like related to log information transfer with the standby online system 22 are further performed. In the online system, in addition to this, establishment of a communication session with a terminal, preparation for switching, and the like are also performed, but these are not shown in FIGS. 1 and 2 because they are outside the scope of this embodiment.

  On the other hand, the standby online system 22 performs the same initial setting as the standby system (step 222). At this time, the mutual monitoring state by the monitor processing unit 11 and the monitor processing unit 21 is started.

  When the mutual monitoring state is started, the execution online system 12 processes a business transaction (step 123).

  When the log information 124 acquired by the business transaction for performing the reference process or the update process is transferred to the standby online system 22, the standby online system 22 refers to and updates the transaction state and database records in the memory according to the log information 124. The state is tracked (step 223). At this time, since the log file 30 and the database 40 are updated from the execution online system 12, the standby online system 22 does not write to these external storage devices, and the database index reference state and record update state. Even tracking is performed only on the database I / O buffer 23 in memory.

  When a failure occurs in the execution online system 12 (step 125), the monitor processing unit 11 or the monitor processing unit 21 detects the failure and switches the execution right of the business transaction to the standby online system 22 (step 126).

  When the failure remains only in the execution online system 12, the monitor processing unit 11 detects the failure and notifies the monitor processing unit 21. If the entire host computer 10 fails and even the monitor processing unit 11 cannot operate normally, the control message (Alive message) from the monitor processing unit 11 to the monitor processing unit 21 is interrupted. A failure of the execution online system 12 which is the partner system is detected.

  When switching to the standby online system 22 occurs, after waiting for the tracking of the unprocessed log information 124 to be completed (step 224), a new business transaction service is started (step 225) and in parallel is not completed. The transaction is rolled back (return and return) (step 226).

  FIG. 3 is a flowchart showing a processing procedure of business transaction processing according to the present embodiment. The business transaction process in step 123 of FIG. 2 will be described with reference to FIG.

  When the transaction is started, a log indicating the start of the transaction is buffered in the log I / O buffer 14 (step 1231). Next, the record is referred to and updated on the database I / O buffer 13 (step 1232), and the record reference log and update log are buffered in the log I / O buffer 14 (step 1233). When the reference or update of the database record in one transaction is completed, the transaction end log is buffered in the log I / O buffer 14 (step 1234), and log information not yet output is forcibly output to the log file 30 (step 1234). Step 1235).

  Here, when reference is made to data that does not exist in the database I / O buffer 13 in step 1232, the reference log is buffered in the log I / O buffer 14 in step 1233. You may reduce the load required for the output and transfer of information.

  FIG. 4 is a flowchart showing a processing procedure of log information buffering processing according to this embodiment. The log information buffering process in steps 1231, 1233, and 1234 of FIG. 3 will be described with reference to FIG.

  First, it is checked whether or not there is a free space in the log I / O buffer that is the current buffering destination (step 12311). If there is a vacancy, the log information is stored in the log I / O buffer (step 12315).

  If there is no space, it is checked whether there is space in another log I / O buffer (step 12312). If a free space is found, the log I / O buffer is set as a new buffering destination (step 12314), and log information is stored (step 12315).

  If there is no empty log I / O buffer, the system waits for an empty space (step 12313). Here, there is a method of dynamically securing a new log I / O buffer when there is no empty log I / O buffer, but it may cause a memory shortage and trigger a failure. Therefore, it is not adopted in this embodiment.

  FIG. 5 is a flowchart showing a processing procedure of the unoutput log forcible output processing of this embodiment. The unoutput log forcible output process in step 1235 of FIG. 3 will be described with reference to FIG.

  First, the log I / O buffer that is the current buffering destination is set to a “no space” state, and new buffering to the log I / O buffer is suppressed (step 12351).

  Next, log I / O buffers that have not been output to the log file 30 are sequentially output (step 12352). This output may be either a synchronous write method in which control does not return until the I / O operation to the external storage device is completed, or an asynchronous write method in which the I / O operation is not completed, but in this embodiment, the standby online system 22 In order to eliminate the influence of the log information transfer process to the transaction of the execution online system 12, an asynchronous writing method is adopted.

  While waiting for completion of writing to the log file 30, the contents of the log I / O buffer targeted at step 12352 are directly written to the log information receiving buffer 25 of the standby online system 22 via the communication medium 51. (Step 12353). It is assumed that the information such as the writing position is grasped from the initial setting time shown in the step 122 and the reply information at the previous writing shown in the step 123.

  Here, when the standby online system 22 is not operating, the step 12353 fails, but the execution online system 12 treats it as successful. This inconsistent state is resolved by reading the difference from the log file 30 up to the latest log information reception buffer 25 log at the time of switching to the standby online system 22. By this processing, it is possible to automatically follow even when the execution system and the standby system are frequently switched as in a seesaw game.

  Next, the completion of the I / O operation in step 12352 is waited (step 12354). The log I / O buffer in which both step 12352 and step 12353 are completed is set as an empty buffer (step 12355).

  FIG. 6 is a flowchart showing the processing procedure of the tracking process of this embodiment. The tracking process in step 223 in FIG. 2 will be described with reference to FIG.

  First, the log information at the end of the log file stored at the time of the initial setting process 222 of the standby online system 22 is compared with the log information sent to the log information reception buffer 25 (step 22301).

  If the log information is discontinuous (specifically, the log file generation number and the log block serial number that is an aggregate of log records are discontinuous, and the intermediate block is missing) The log information 31 is input from the log file 30 to catch up to the time point of the log information receiving buffer 25 (step 22302). The specific method of the catch-up process here is the same as in steps 22303 to 22308 described later.

  Next, the individual log information stored in the log information receiving buffer 25 is sequentially examined, and if it is a log in which a change in the state of the transaction is recorded, such as a transaction start log or transaction end log (step 22303), Management information for each transaction is updated (step 22304).

  If it is a reference log or update log of a database record (step 22305), it is checked whether there is a corresponding page in the database I / O buffer 23 (step 22306), and there is no page of the record in the database I / O buffer 23. For example, the page of the record is read from the database 40 to the database I / O buffer 23 (step 22307). Next, when the log is an update log, the record is updated on the database I / O buffer 23 according to the contents (step 22308).

  The processes in steps 22303 to 22308 are repeated for all the log information in the log information reception buffer 25 (step 22309).

  Next, it is checked whether or not the detection of the failure is notified from the monitor processing unit 11 or the monitor processing unit 21, and it is checked whether or not the own system remains a standby system (step 22310). If the system remains the standby system, it waits for the reception of log information (step 22313) and repeats the processing from step 22303 to step 22308. On the other hand, if switching to the execution system is instructed by detection of a failure by the monitor processing unit 11 or the monitor processing unit 21, business transaction processing is executed as the execution system.

  As described above, according to the online processing system of this embodiment, when a failure occurs in the execution online system, the input / output buffer of the standby online system that has been matched in advance with the contents of the input / output buffer of the execution online system. Since the business process is continued in the standby online system using the system, it is possible to switch to the standby online system at a high speed when a failure occurs in the execution online system.

  Further, according to the online processing system of the present embodiment, when a reference process to data that does not exist in the input / output buffer of the execution online system is performed, the reference history is transferred to the standby online system as log information. It is possible to reduce the transfer load of log information for matching the contents of the input / output buffer in the standby online system with the contents of the input / output buffer in the execution online system.

  Further, according to the online processing system of the present embodiment, when the log information subjected to the tracking process and the log information transferred from the execution online system are not continuous, the log information between them is read from the storage device, Since the I / O buffer in the standby online system is added, if the standby online system is restarted after a failure or maintenance, the hot standby state is not affected without affecting the execution of business processing in the execution online system. Re-establishment is possible.

It is a figure which shows schematic structure of the online processing system of this embodiment. It is a flowchart which shows the process sequence of the execution online system 12 and the standby online system 22 of this embodiment. It is a flowchart which shows the process sequence of the business transaction process of this embodiment. It is a flowchart which shows the process sequence of the buffering process of the log information of this embodiment. It is a flowchart which shows the process sequence of the forced output process of the non-output log of this embodiment. It is a flowchart which shows the process sequence of the tracking process of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Host computer, 12 ... Execution online system, 13 ... Database I / O buffer, 14 ... Log I / O buffer, 20 ... Host computer, 22 ... Standby online system, 23 ... Database I / O buffer, 24 ... Log I / O buffer, 25 ... log information reception buffer, 30 ... log file, 31 ... log information, 40 ... database, 50 and 51 ... communication medium, 11 ... monitor processing unit, 15 ... log output processing unit, 16 ... log transfer processing , 21 ... monitor processing unit, 27 ... tracking processing unit, 124 ... log information.

Claims (5)

In an online system recovery method that switches business processing to a standby online system and continues when a failure occurs in the execution online system,
A step of transferring log information representing a reference history indicating a history of reference processing performed in the execution online system and an update history indicating a history of update processing to the standby online system; and the standby online system according to the transferred log information Performing a tracking process to match the contents of the I / O buffer in the execution online system with the contents of the I / O buffer in the online system;
The operating status of the execution online system that is executing the business process is monitored, and when a failure of the execution online system is detected, the business process is continued in the standby online system using the input / output buffer that has been subjected to the tracking process. And an on-line system recovery method.   The reference history transferred to the standby online system as the log information indicates a history of reference processing to data that does not exist in the input / output buffer of the execution online system. Online system recovery method.   When the step of outputting the log information to a storage device shared by the execution online system and the standby online system and the log information subjected to the tracking process and the log information transferred from the execution online system are not continuous In the meantime, the log information is read from the storage device, and the contents of the input / output buffer in the standby online system are matched with the contents of the input / output buffer in the execution online system according to the read log information and the transferred log information. The online system recovery method according to claim 1, further comprising a step. In an online processing system that switches business processing to a standby online system and continues when a failure occurs in the execution online system,
In accordance with the log transfer processing unit for transferring the log information representing the reference history indicating the history of the reference processing performed in the execution online system and the update history indicating the history of the update processing to the standby online system, according to the transferred log information, A tracking processing unit for performing a tracking process for matching the contents of the input / output buffer in the standby online system with the contents of the input / output buffer in the execution online system;
The operating status of the execution online system that is executing the business process is monitored, and when a failure of the execution online system is detected, the business process is continued in the standby online system using the input / output buffer that has been subjected to the tracking process. An on-line processing system comprising a monitor processing unit. In a computer-readable recording medium in which a program for causing a computer to function as an online processing system that switches a business process to a standby online system and continues when a failure occurs in the execution online system,
In accordance with the log transfer processing unit that transfers log information representing the reference history indicating the history of the reference processing performed in the execution online system and the update history indicating the history of the update processing to the standby online system, according to the transferred log information, A tracking processing unit for performing tracking processing for matching the contents of the input / output buffer in the standby online system with the contents of the input / output buffer in the execution online system;
The operating status of the execution online system that is executing the business process is monitored, and when a failure of the execution online system is detected, the business process is continued in the standby online system using the input / output buffer that has been subjected to the tracking process. A recording medium on which a program for causing a computer to function as a monitor processing unit is recorded.

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